Pumps for liquids

ABSTRACT

A pump for a liquid comprises a housing a first chamber in the housing, an inlet and an outlet for said front chamber a second chamber in the housing sealingly separated from the first chamber, an electric motor in the second chamber, a third chamber between the first and second chambers, an outlet from said third chamber, a main impeller in the first chamber, an anusiliary impeller in the third chamber to urge any fluid leaking from said first and second chamber to the outlet.

Feb. 5, 1974 United States Patent 91 Bottoms 3,495,537 2/1970 Archibald417/424 3,513,942 5/1970 Sato...... 417/424 3,652,186 3/1972Carter................................. 4l7/424 PUMPS FOR LIQUIDS [76]Inventor: Harry Simister Bottoms, 4O Kineton Green Rd., Solihull,England July 24, 1972 Appl. No.: 274,295

Primary Examiner-C. J. Husar [22] Filed:

Attorney, Agent, or Firm-John C. Holman et al.

[57] ABSTRACT A pump for a liquid comprises a housing a first cham- [30]Foreign Application Priority Data July 23, 1971 ber in the housing, aninlet and an outlet for said front chamber a second chamber in thehousing sealingly separated from the first chamber, an electric motor inGreat Britain................... 34,551/71 [52] US. Cl. 417/424 [51]Int. F04b 17/00 the second chamber, a third chamber between the firstand second chambers, an outlet from said third chamber, a main impellerin the first chamber, an anusiliary impeller in the third chamber tourge any fluid leaki from said first and second chamber to the outlet.

[58] Field of 417/424 [56] References Cited UNITED STATES PATENTS2,470,563 5/1949 Jennings 417/424 3 Claims, 1 Drawing Figure i PUMPS FORLIQUIDS This invention relates to pumps for liquids, and has as anobject to'provide such a pump in a convenient form.

According to the invention a pump for a liquid comprises a housing, afirst chamber within the housing, an

- inlet and an outlet for said first chamber, a second An example of theinvention will now be described with reference to the accompanyingdrawing which shows a longitudinal section through a pump.

The pump has a housing with an inlet 11 at one end thereof. Brackets 12extend from the housing adjacent the inlet 11 whereby the pump may bemounted on the bottom 13 of a tank containing a liquid fuel. Sealinglysecured within the housing 10 is a block 14 which in part defines avolute chamber 15. Chamber 15 communicates with an outlet 16 in thehousing 10.

Sealingly mounted on the block 14 is a plate 17 which defines a chamber18 within the'housing 10. A further chamber 19 is defined between theplate 17 and block 14, and communicates with an annular passage 20 inthe block 14. Passage 20 communicates in turn with a second outlet 21 inthe housing 10. Within chamber 18 is an electric motor, shown generallyat 22, whose shaft 23 passes through a sealed and prelubricated bearing24 supported by plate 17. Shaft 23 also passes through a labyrinth seal25 in plate 17, through chamber 19 and through a shaft sealingarrangement 31 in block 14 to the chamber 15.

Surrounding motor 22 within housing 10 is a space 26. Space 26communicates via a conduit 27 with atmosphere, supply cables for motor22 being also led through conduit 27. Secured to shaft 23 within chamber15 is a centrifugal impeller 28. Also secured to shaft 25 within chamber19 is a further centrifugal impeller 29. A passage 30 permits space 18to communicate with the side of bearing 24 remote from motor 22.

In use, the impeller 28 operates in a known manner to draw fuel frominlet 11 and to discharge it via outlet 16. Air leaking from chamber l8into chamber 19, via passage 30, and labyrinth 25, is urged by impeller29 to outlet 21, which is connected to a drain. Fuel leaking pastsealing arrangement 31 into chamber 19 is also discharged via outlet 21.The substantially constant flow of air through labyrinth 25 into chamber19 ensures that no fuel or vapour passes to bearing 24 or the chamber18.

Any fuel vapour which may be present within chamber 18 is thus withdrawnvia passage 30 and labyrinth 18 and expelled via outlet 21. Bearing 24is thus exposed to fuel vapour for a minimum time and this vapourbypasses bearing 24 via passage 30. Lubricant within bearing 24 doesnot, therefore, deteriorate as a result of exposure to fuel vapour.

I claim:

1. A pump for a liquid comprising a housing, a first chamber within thehousing, an inlet and an outlet for said first chamber a second chamberwithin the housing sealingly separated from said first chamber, anelectric motor within said second chamber, a third chamber within thehousing between said first and second chambers and sealingly separatedtherefrom, an outlet from said third chamber, a first impeller in saidfirst chamber drivable by the motor to urge liquid from the inlet to theoutlet of said first chamber, and a second impeller in the third chamberdrivable by the motor to urge fluid leaking from said first and secondchambers to the third chamber outlet.

2. A pump as claimed in claim 1 in which there is provided a labyrinthsea] separating the second chamber from the third chamber, secondimpeller causing, in use, a substantially constant flow of air from saidsecond chamber to said third chamber through said labyrinth seal so asto prevent any liquid which enters said third chamber passing throughsaid labyrinth seal.

3. A pump as claimed in claim 2 including a sealed bearing supportingthe motor shaft adjacent said labyrinth seal, said housing being formedwith at least one by-pass passage adjacent said bearing through whichair passes towards said labyrinthseal whereby no pressure drop iscreated across said bearing.

1. A pump for a liquid comprising a housing, a first chamber within thehousing, an inlet and an outlet for said first chamber a second chamberwithin the housing sealingly separated from said first chamber, anelectric motor within said second chamber, a third chamber within thehousing between said first and second chambers and sealingly separatedtherefrom, an outlet from said third chamber, a first impeller in saidfirst chamber drivable by the motor to urge liquid from the inlet to theoutlet of said first chamber, and a second impeller in the third chamberdrivable by the motor to urge fluid leaking from said first and secondchambers to the third chamber outlet.
 2. A pump as claimed in claim 1 inwhich there is provided a labyrinth seal separating the second chamberfrom the third chamber, second impeller causing, in use, a substantiallyconstant flow of air from said second chamber to said third chamberthrough said labyrinth seal so as to prevent any liquid which enterssaid third chamber passing through said labyrinth seal.
 3. A pump asclaimed in claim 2 including a sealed bearing supporting the motor shaftadjacent said labyrinth seal, said housing being formed with at leastone by-pass passage adjacent said bearing through which air passestowards said labyrinth seal whereby no pressure drop is created acrosssaid bearing.